Mitsubishi Electric UH

What does Mitsubishi Electric UH mean?

The control detected an error in the current sensor that monitors compressor current, and stopped the unit with UH on a blinking display. Because the system relies on accurate current sensing to protect the compressor and inverter, an out-of-range or faulty current reading disables operation. The fault is typically in the sensing circuit on the control board rather than the refrigerant side.

Symptoms

• UH shown on a blinking display
• Unit stops on the protection device
• Fault appears even with otherwise normal operation
• Code recurs after restart

Common causes

• Faulty current sensor on the control board
• Loose or damaged wiring in the sensing circuit
• Control board (inverter) fault
• Abnormal supply affecting the current reading

Diagnostic steps

1. 01

   Power down the unit

   Switch off the outdoor unit before inspecting the electrical box.

2. 02

   Check the supply

   Confirm correct, stable voltage at the outdoor unit power terminals.

3. 03

   Look for loose connections

   Inspect the control board and harnesses for loose or damaged connectors.

4. 04

   Attempt one reset

   Restore power and note whether UH clears or returns immediately.

5. 05

   Arrange board service

   If UH persists, the current-sensing circuit or control board needs technician inspection.

When to call a professional

Call a technician for UH, since the current sensor is part of the inverter control board and requires meters and service data to diagnose. Testing and replacing the control board involves high-voltage work inside the outdoor unit. A qualified HVAC professional should confirm the current-sensor fault and perform any board replacement.